Fiesta Timing belt change disaster - duratec 1.6 2005

[EdGasket]

So I read up lots on this, got a flywheel locking tool and timing pins, watched lots of youtube videos BUT have still ended up with suspected bent valves.

Here's what I did and what I think has gone wrong:

1) Timed engine using pin and clamped flywheel using locking tool

2) Fitted cambelt with cambelt bar tool in the slots. So at this stage everything is timed and engine locked at flywheel

3) Removed timing pin and bar from the cams as I didn't want to break or bend anything while doing up the crank pulley. Flywheel still locked, cam slots level.

4) Tightened crank bolt 33 ft lbs then a further 90 degrees using 3/4 socked set and breaker bar

Then once I got up from doing up the crank bolt I noticed the cams had advanced about 25 degrees??

To my horror I found that on removing the flywheel locking tool, I could not turn the engine; it was butted up against the valves. I did not expect this as the engine was locked at the flywheel. What I think happened is that the pulley must have turned as I was tightening the bolt and, even though the engine was locked, it dragged the timing sprocket round and moved the cams until a valve or two butted up against a piston.

I then removed the pulley bolt, re-timed everything and this time did up the bolt using an impact gun as per many of the youtube videos. I found the cams still moved a little using this method so had to loosed the cam bolts and bring them back into time.

Now the engine runs but is rough and shaking with occasional pops from the exhaust if I rev up.

My questions are:

1) How the heck are you supposed to do this job? I watched every video, took every precaution. No one mentioned that doing up the pulley bolt might drag the cams round and bend valves except Haynes says to hold the pulley with a homemade tool but my pulley has no holes in it to do that so impossible. ( I think if I'd used just an impact, I'd have got away with it as that didn't turn the cams too much but still risky)

2) Does it sound like a need to get the head off now? Would manually tightening the crank bolt exert enough force through the timing belt to bend a valve in slow motion - I wouldn't have thought so but then I was putting a lot of force on the pulley bolt. I have a compression tester and an extension but neither will fit down the narrow access to the spark plug holes so I am unable to do a compression test.

Needless to say I am hacked off and hate this engine with no keyways!

 

[EdGasket]

Panic over, I hope.

I got a P0304 code, misfire cylinder 4. I must have damaged the spark plug getting it out or in as the porcelain was cracked. Replaced and, fingers crossed, car seems to be running OK.

 

I would still like to have any views on the best way to prevent the cams turning while tightening the crank bolt and whether breaker bar or impact gun is best for tightening?

 

[rd457]

6 hours ago, EdGasket said:

3) Removed timing pin and bar from the cams as I didn't want to break or bend anything while doing up the crank pulley. Flywheel still locked, cam slots level.

Wise choice, when studying how to do my own I recall seeing someone who did not remove the bar and a big chunk of camshaft violently broke off, and another (or was it the same person?) who did not remove the pin which then got bent creating a hugely difficult task to remove it.

6 hours ago, EdGasket said:

4) Tightened crank bolt 33 ft lbs then a further 90 degrees using 3/4 socked set and breaker bar

Overkill, you only potentially need 3/4" stuff for bigger things like lorries. 1/4" and 3/8" will do for most smaller stuff in a car, and 1/2" for the bigger things like lugnuts, the crankshaft pulley bolt and such.

6 hours ago, EdGasket said:

Then once I got up from doing up the crank bolt I noticed the cams had advanced about 25 degrees??

To my horror I found that on removing the flywheel locking tool, I could not turn the engine; it was butted up against the valves. I did not expect this as the engine was locked at the flywheel. What I think happened is that the pulley must have turned as I was tightening the bolt and, even though the engine was locked, it dragged the timing sprocket round and moved the cams until a valve or two butted up against a piston.

I then removed the pulley bolt, re-timed everything and this time did up the bolt using an impact gun as per many of the youtube videos. I found the cams still moved a little using this method so had to loosed the cam bolts and bring them back into time.

Reviewing what details you've provided of the procedure you followed, it seems that you did not loosen the camshaft sprocket bolts prior to tightening the crankshaft pulley bolt. If you had done so then the crankshaft pulley, the cambelt cog/sprocket behind it, the belt and the camshaft sprockets may have all turned a bit as you tightened down the bolt, as you found them to, but crucially this would have happened without turning the camshafts at all. Then you would have tightened down the camshaft sprockets afterwards (ideally with fresh bolts) whilst preventing the camshafts from turning using either a counterhold tool on the sprockets, or a spanner on the hexagonal portion of the camshafts themselves.

[EdGasket]

Thanks that's very clear and logical now. I was trying to leave the cam bolts untouched as I had seen a couple of youtube videos where they appear to have done that and then just hammering up the crank with an impact.

Why do you need fresh cam bolts, they are not torque to yield are they? I just loosened a bit and re-tightened the existing bolts to 44 ft lbs

[rd457]

1 hour ago, EdGasket said:

Why do you need fresh cam bolts, they are not torque to yield are they? I just loosened a bit and re-tightened the existing bolts to 44 ft lbs

They are on my Mk2.5 ('08) 1.6 Focus. I'm just assuming they would also be on your Fiesta. I could be wrong but it is the same torque spec, so probably identical.

I wouldn't worry about it though, as you perhaps know, the whole TTY thing is that they get stretched permanently a bit, and each time they get installed and thus stretched again this adds up and adds up getting towards the point where they will snap. The recommendation is to treat TTY bolts as single use and always replace them, you're taking a risk if you don't, but I expect your camshaft bolts will be fine with just the one extra stretch. If you didn't replace the crankshaft bolt with a fresh one then it's thus been stretched three times which I'd consider a little dodgy, I've no idea how many stretched it'd take before snapping.

[EdGasket]

Do you think a lot of stress would have been put on the timing belt the first time I did up the crank bolt manually and it dragged the cams round until they touched a piston? Then the timing belt and cam sprocket could rotate no more due to the camshaft being locked up but I was still turning the bolt which would have been trying to rotate the pulley. Although at that point the sprocket would also be butted up against the locked locked engine which would help the crank sprocket to remain stationary. Hard to know I guess. Well I'm not going to do the whole job again so no point stressing about it I guess.

[rd457]

Yeah my guess would be only as good as yours on that point. The other concern would be whether or not the pistons and valves incurred any damage, as I believe they're only made out of aluminium like the engine block.

[agraham]

The valve are certainly not made of aluminium. They will be a high temperature resistant stainless steel alloy of some sort.